Pump body and method for making same

ABSTRACT

A pump of the type comprising a substantially cylindrical body ( 1 ) in one piece provided, in its lower part, with a port ( 11 ) for admission of a product and with a valve constituted by a cavity ( 10 ) containing an element ( 2 ) capable of moving between a lower stop ( 12   b ) corresponding to the obturation of said admission port ( 11 ) and an upper stop ( 12   a ) corresponding to the opening of said port ( 11 ), and wherein said upper stop ( 12   a ) is formed by at least one discontinuous internal projection ( 12 ) whose transverse dimension (x) measured in the cavity ( 10 ) is at least equal to 20% of the largest transverse dimension of the mobile element ( 2 ).

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a pump and more particularly to animprovement in the inlet valve of the pump as well as to a process formanufacturing such a pump.

2. Related Art

The invention concerns pumps of the type comprising in particular asubstantially cylindrical body in one-piece, provided in its lower partwith a port for admission of the product and with a valve. This valve isconstituted in known manner by a cavity forming seat and containing anelement capable of moving between a lower stop corresponding to aposition of obturation of the admission port and an upper stopcorresponding to the opening of said port and to the filling of the pumpbody by the product.

The stroke of the mobile element which is generally constituted by aball, must be adjusted so as to obtain the regular delivery by the pumpof identical, constant doses.

Consequently, the upper and lower stops must be positioned withprecision.

According to a known solution, the upper stop is constituted by thelower turn of a helicoidal return spring housed in the pump body.

However, this spring creates problems of bulk and/or of compatibilitywith the product.

A variant embodiment of this upper stop consists in fixing an addedpiece in the lower part of the pump body above the mobile element.

However, the production of this piece and its assembly in the pump arecomplex and expensive operations.

In addition, it is necessary to arrange on the pump body specific meansfor fixing this piece.

Another solution lies in the presence of retaining bosses mouldeddirectly in the pump body like in U.S. Pat. No. 2,294,568.

These bosses project inside the pump body and define towards the top thecavity in which the mobile element is housed.

However, the transverse dimension of these bosses measured from theinner wall of the body always remains small with respect to the innerdiameter of the cavity in order to allow unmoulding of the body and thesubsequent introduction of the mobile element in the cavity. For thesame reasons, the section of these retaining bosses comprises neitherangular zone nor free edge in undercut. Nonetheless, despite this, theprojecting bosses are sometimes crushed upon ejection from the mould,which considerably compromises the subsequent reliability of the pumpinsofar as the mobile element can then escape from its cavity.

In the Patent Abstracts of Japan Vol. 15 No. 392 of Oct. 4, 1991 andJP-A-316 1066, the upper stop of the mobile element of the valve isensured by means of discontinuous internal projections performed bycut-out using a tool incorporating a blade whose profile is bevelled.

Moreover, the non-aggressive profile of these projections promotes thejamming of the mobile element in the top of the cavity, which increasesthe risks of dysfunction of the pump.

All these problems are even more substantial when the pump is aminiature pump, intended for example for samples of perfume ordispensers of small doses of medicaments.

It is an object of the present invention satisfactorily to solve thetechnical problems raised by the prior art.

BRIEF SUMMARY

This object is attained in accordance with the invention by a pump ofthe type comprising in particular a substantially cylindrical body inone piece provided, in its lower part, with a port for admission of theproduct and with a valve constituted by a cavity containing an elementcapable of moving between a lower stop corresponding to the obturationof said admission port and an upper stop corresponding to the opening ofsaid port, wherein said upper stop is formed by at least onediscontinuous internal projection whose transverse dimension measured inthe cavity is at least equal to 20% of the largest transverse dimensionof the mobile element.

According to an advantageous characteristic, said projection has aninner edge of which the generatrices are substantially parallel to theaxis of the body.

Diameter is included between 50% and 90% of the largest transversedimension of the mobile element.

According to other characteristics, the upper face of said projection iswider than its lower face.

Said projection preferably presents, outside said cavity, an at leastpartly cylindrical cut out of which the generatrices are parallel to theaxis of the body.

According to a particular embodiment, the upper stop comprises fourprojections diametrally opposite in two's.

These four projections are preferably separated by free sectors capableof allowing the product to pass.

According to a specific variant, the free sectors have an angular lengthincluded between 30° and 80°.

Another object of the invention is a process for manufacturing a pump,characterized in that the pump body is produced, then at least onediscontinuous internal projection is formed by fashioning the inner wallof said body by means of a punching die, of which the diameter of thehead is included between 110% and 140% of the largest transversedimensions of the mobile element.

The transverse dimension of the internal projection, the diameter of theupper orifice of the cavity as well as the diameter of the head of thepunching die are parameters which are chosen with reference to thelargest transverse dimension of the mobile element but which also dependon the depth of penetration of the punching die in the wall of the bodyof the pump. This depth is limited by the available wall thickness inthe zone intended for fashioning and, for determining the values of theabove parameters, was fixed at 25% of the wall thickness of the pumpbody.

According to an advantageous characteristic, said body is fashionedinternally by the punching die pushing the matter constituting the walldownwardly and inwardly, so as partly to close the cavity.

According to another characteristic, said body is fashioned internallywith a punching die incorporating four blades diametrally opposite intwo's.

According to yet another characteristic of the process, the mobileelement is introduced in the lower part of the body, prior to theformation of said internal projection.

The pump of the invention thus comprises a particularly reliable andprecise inlet valve. With such a valve, the risks of the mobile elementjamming or escaping are virtually non-existent.

In addition, the process of the invention makes it possible to produceprojections whose transverse dimension is so large that they could notbe made by moulding and which, moreover, would not allow the subsequentpositioning of the mobile element.

The process of the invention also enables projections of variousdimensions to be made on the same type of pump body, which allows mobileelements of different sizes to be used.

DESCRIPTION OF THE DRAWINGS

The invention will be more readily understood on reading the followingdescription with reference to the accompanying drawings, in which:

FIG. 1 shows a view in section of a pump body according to the priorart.

FIGS. 2a and 2 b show detailed views in section of an embodiment of apump body according to the invention, respectively in position ofclosure of the valve and in position of opening thereof.

FIGS. 3a and 3 b show partial plan views of the pump body respectivelybefore and after fashioning.

FIG. 4a shows a view in profile of a punching die used by the process ofthe invention.

FIG. 4b shows a view from underneath of the punching die of FIG. 4a.

FIG. 5 shows a view in section of the pump body while the process of theinvention is being carried out.

DETAILED DESCRIPTION

The body 1 shown in FIG. 1 corresponds to that of a conventional pump Aused, for example, for sprays of liquids such as perfumes.

The body 1 is substantially cylindrical and is made in one piece, forexample by injection moulding of a thermoplastics material.

The body is provided in its lower part 1 a with an admission port 11supplied with product from a tank (not shown) and possibly extendeddownwardly by an immersion tube.

The admission port 11 opens out via an orifice 11 a on a valveconstituted by a cavity 10 containing a mobile element such as a ball 2.

The ball 2 is capable of moving axially between a lower stop 12 bcorresponding to the obturation of the port 11 and therefore to theclosure of the valve, and an upper stop 12 a corresponding to theopening of said valve and to the passage of the product towards chamberB of pump A.

The lower stop 12 b is formed by the truncated wall of the cavity 10against which the ball 2 comes into tight stop.

The upper stop 12 a is here formed by retaining elements made directlyby moulding with the pump body assembly, in the tipper part of thecavity 10.

These retaining elements are bosses which offer the ball 2 slightlyprojecting curvilinear contact surfaces, i.e. each boss has a transversedimension of at the most 20% of the radius R of the ball 2, which isinsufficient to guarantee perfect functioning of the valve.

Between these bosses are arranged lateral passages for the product.

FIGS. 2a and 2 b represent partial views in section of an embodiment ofthe body 1 of a pump according to the invention, respectively inposition of closure and of opening of the valve.

Here, the upper stop 12 a is formed by at least one internal projection120 made on the upper periphery of the cavity 10 and discontinuously,forming at least one lateral passage for the product around the ball 2.

The transverse dimension X of the projection 12 a measured in theconico-cylindrical cavity 10 is at least equal to 20% of the largesttransverse dimension of the mobile element and therefore of the diameterof the ball 2 or to 40% of its radius R.

The cavity 10 is therefore defined and partly closed in its upper partby a transverse wall portion whose total length corresponds to twice thetransverse dimension X, viz. at least 40% of the diameter of the ball 2(or to 80% of the radius R), which guarantees a blockage of the ball intranslation without jamming.

The upper orifice 10 a of the cavity 10 is therefore relatively narrowand its diameter is included between 50% and 90% of the largesttransverse dimension of the mobile element which corresponds here to thediameter of the ball 2.

The projection 120 presents an inner edge 120 c of which thegeneratrices are substantially parallel to the axis of the body 1.

The projection 120 presents, outside the cavity 10, an at least partlycylindrical cut-out 13 of which the generatrices are substantiallyparallel to the axis of the body 1.

The upper face 120 a of the projection 120 which faces the outside ofthe cavity 10 is wider than the lower face 120 b which, for reasons ofsimplification, is shown here to be parallel to the upper face 120 a andperpendicular to the inner wall of the cavity 10 in its upper part.

In accordance with a variant embodiment (not shown), the lower face 120b of the projection 120 is inclined, curvilinear or constituted by aswell but in no case does it present a zone of contact with the ball 2in upper stop position in order to avoid any guiding or slide of theball out of the cavity 10.

In the position of opening of the valve, shown in FIG. 2b, the ball isblocked in translation by the upper stop 12 a, by coming into abutmentagainst the join between the inner edge 120 c and the lower face 120 bof the projection 120.

Consequently, the zone of contact between the projection 120 and theball 2 is materialized by a substantially circular line on which theforces of stop are directed radially with respect to the ball so as toavoid any jamming.

FIGS. 3a and 3 b correspond to an embodiment with four projections 120,121, 122, 123, diametrally opposite in two's, on the upper periphery ofthe cavity 10. The ball 2 has not been shown in these Figures.

The cut-outs 12 are interrupted at the level of the discontinuities ofthe projections 120, 121, 122, 123 to define free sectors 14.

On the sectors 14, the profile of the inner wall of the pump body hasnot been modified and is therefore smooth and continuous, so as topresent no obstacle from the inside to the outside of the cavity 10 inorder to allow free passage of the product.

Projections 120, 121, 122, 123 are here centred, on either side, on twoperpendicular diameters.

Their respective inner edges 120 c, 121 c, 122 c, 123 c present a lengthsuch that the intermediate free sectors 14 correspond to portions ofangles α included between 30° and 80°.

The pump A of the invention, and in particular the body 1 of said pumpis made in conventional manner, for example, by injection moulding ofplastics or thermoplastics material.

By fashioning the inner wall of the body 1, at least one discontinuousinner projection 120 is made, and preferably four projections separatedby free sectors, by fashioning the inner wall of the body 1.

The ball 2 is preferably introduced in the lower part 1 a of the body 1prior to fashioning, when the inner wall is still uniform.

However, if the inner projection 120 is elastically deformable and/orflexible, it is then possible to proceed with introducing the ball afterfashioning, by deforming stop on said projection.

This fashioning or stamping operation is effected by means of a punchingdie P such as the one shown in FIGS. 4a and 4 b.

The punching die P comprises a mandrel M bearing a head T. The mandrel Mensures centering, guiding and wedging of the punch in the pump bodyduring fashioning.

The head T ensures fashioning of the body by forced, axial translationof the mandrel M as shown in FIG. 5.

To that end, the head T comprises at least one and, in the present case,four blades L intended to push the matter on the wall of the body 1above and around the ball 2, forming cut-outs 13, and the projections120, 121, 122, 123 as shown in FIG. 5.

The diameter d of the head is included between 110% and 140% of thediameter of the ball for a depth of penetration of about 25% of thethickness of the wall of the body.

The geometry of the blades L shown from underneath in FIG. 4b,determines the subsequent geometry of the cut-outs 13, the projections120, 121, 122, 123 and the free sectors 14.

The lower face C of blades L acts by its outer edge in the manner of aknife or a tooth with respect to the plastics material, causing it tocreep towards the interior of the head.

The width and length of the lower face C is previously determined as afunction of the dimensions sought for the projections.

The transverse dimension X of the projections to be made will depend onthe volume of matter pushed downwardly and inwardly by each of theblades L on the inner periphery of the cavity 10. This volume thereforecorresponds to the volume defined by the cut-outs 13. Now, this volumeis itself a function of the diameter of the head T, of the width x ofthe lower face C and of the depth of penetration, of the angular lengthy and of the height h of the blades L.

The outer face 1 of the blades L is straight and parallel to the axis ofthe mandrel M while their inner face 1′ is inclined towards the mandrelM and towards the centre of the head T by an angle β close to 45° inorder not to stress the ball while the head is working.

The mandrel M comprises a face E intended to abut against a shoulder 1 bof the pump body (cf. FIGS. 2a and 2 b) in order to limit penetration ofthe head T.

Consequently, the position of the upper stop 12 a, and therefore thestroke of the ball 2, will be determined as a function of the height hof the blades L with respect to face E of the mandrel.

What is claimed is:
 1. A pump of the type comprising a substantiallycylindrical body (1) in one piece provided, in its lower part, with aport (11) for admission of the product and with a valve constituted by acavity (10) containing an element (2) capable of moving between a lowerstop position (12 b) corresponding to the obturation of said admissionport (11) and an upper stop position (12 a) corresponding to the openingof said port (11) and that is defined by at least one discontinuousinternal projection (120) whose lowerface (120 b) partly closes saidcavity and whose upperface (120 a) is topped, outside said cavity, withan at least partly cylindrical cut-out (13) whose generatrices areparallel to the axis of the body (1), and wherein said projection (120)defines an inner edge (120 c) the generatrices of which aresubstantially parallel to the axis of the body (1) and which defines, atthe junction of the lower face (120 b)with the mobile element (2) a linecontact in the upper stop position enabling avoidance of any jamming orsliding of said element outside the cavity (10).
 2. The pump accordingto claim 1, wherein said mobile element is a ball housed in aconico-cylindrical cavity (10) which, in the upper stop position, abutsradially against a circular line contact defined by said projection(120).
 3. The pump according to claim 1, wherein said cavity (10)defines an upper orifice (10 a) laterally defined by the internalprojection (12) and of which the inner diameter is included between 50%and 90% of the largest transverse dimension of the mobile element (2).4. The pump according to claim 1, wherein the surface of the upper face(120 a) of said projection (120) is wider than the surface of the lowerface (120 b).
 5. The pump according to claim 1, wherein the upper stop(12 a) comprises four projections (120, 121, 122, 123) diametricallyopposed in pairs.
 6. The pump according to claim 5, wherein the fourprojections are separated by free sectors (14) capable of allowing aproduct to pass.
 7. The pump according to claim 5, wherein the freesectors (14) present an angular length included between 30° and 80°. 8.A process for manufacturing a pump as defined in claim 1, comprising thesteps of producing the pump body (1) with at least said onediscontinuous internal projection (120) formed on the inner wall of saidbody by using a punching die (P), wherein said projection (120) isformed by said die with an inner edge (120 c) the generatrices of whichare parallel to the axis of said body and which inner edge defines atthe junction of the lower face (120 b) a circular contact line with themobile element (2) in the upper stop position.
 9. The process accordingto claim 8, wherein said body is internally formed by the punching die(P) by pushing the material constituting the wall downwardly andinwardly so as to partly close the cavity (10).
 10. The processaccording to claim 8, wherein said body (1) is internally formed byusing said punching die (P) incorporating four blades (L) diametrallyopposite in pairs.
 11. The process according to claim 8, includingintroducing the mobile element (2) in the lower part of the body (1)prior to the step of forming of said internal projection (120).
 12. Thepump according to claim 1, wherein said projection includes a lower face(120 b) extending perpendicular to the axis of the body (1).